Signal-selecting system for an electronic musical instrument

Claim 2

A transistor preference circuit comprising: an electric power source; a plurality of keyswitches, each having one end connected to one end of said electric power source; a plurality of bias resistors connected in series with each other, one end of said series connection of said bias resistors being connected to the other end of said electric power source; a plurality of collector resistors coupled to the other end of said electric power source; a plurality of transistors having the emitters thereof connected to the other ends of the respective keyswitches, the bases thereof connected to the junction points of the respective bias resistors and the other end of said series connection of said bias resistors, respectively, and the collectors thereof connected to the respective collector resistors and being provided with a potential substantially equal to the potential of the other end of said electric power source; and a plurality of base resistors connected between the bases and the collectors of the respective transistoRs; whereby when one or more keyswitches are simultaneously closed, only the transistor, the base of which is connected to the junction point closest to the other end of said electric power source among the transistors corresponding to the closed keyswitches, is made conductive and produces an output control voltage at the collector thereof.

Claim 3

A signal selecting system for an electric musical instrument comprising: a plurality of tone generators generating tone signals having frequencies corresponding to the notes of the musical scale, respectively; a plurality of gating means coupled to the respective tone generators for gating said tone signals; a first electric power source; a plurality of keyswitches corresponding to said tone generators and each having one end connected to one end of said electric power source; and a preference circuit which comprises a plurality of bias resistors connected in series and one end of said series connection being connected to the other end of said electric power source; a plurality of transistors; a plurality of base resistors connected between the bases and the collectors of the respective transistors; and a plurality of collector resistors connected to said collectors of the respective transistors and being coupled to the other end of said first electric power source, the emitters of said plurality of transistors being connected to the other ends of the respective keyswitches, the bases of said plurality of transistors being connected to the junction points of the respective bias resistors connected in series and the other end of said series connection of said bias resistors, respectively, and said collectors of said plurality of transistors being provided with a potential substantially equal to the potential of the other end of said electric power source through said collector resistors, said collectors being coupled to said gating means for controlling the gating operation of said gating means and the supply of tone signals thereto from said tone generators; whereby when one or more keyswitches are simultaneously closed, only the transistor, the base of which is connected to the junction point closest to said other end of said electric power source among the transistors corresponding to the closed keyswitches, is made conductive and the corresponding gating means is actuated so as to select preferentially only one output tone signal.

Claim 4

A signal selecting system for an electric musical instrument comprising: a plurality of tone generators generating tone signals having frequencies corresponding to the notes of the musical scale, respectively; a plurality of gating means coupled to the respective tone generators for gating said tone signals; a first electric power source; a plurality of keyswitches corresponding to said tone generators and each having one end connected to one end of said electric power source; and a preference circuit which comprises a plurality of bias resistors connected in series and one end of said series connection being connected to the other end of said electric power source; a plurality of transistors; a plurality of base resistors connected between the bases and the collectors of the respective transistors; and a plurality of collector resistors connected to said collectors of the respective transistors and being coupled to the other end of said first electric power source, the emitters of said plurality of transistors being connected to the other ends of the respective keyswitches, the bases of said plurality of transistors being connected to the junction points of the respective bias resistors connected in series and the other end of said series connection of said bias resistors, respectively, and said collectors of said plurality of transistors being provided with a potential substantially equal to the potential of the other end of said electric power source through said collector resistors, said collectors being coupled to said gating means for controlling the gating operation of said gating means and the supply of tone signals thereto from said tone generators; whereby when one or more keyswitches are simultaneously closed, only the transistor, the base of which is connected to the junction point closest to said other end of said electric power source among the transistors corresponding to the closed keyswitches, is made conductive and the corresponding gating means is actuated so as to select preferentially only one output tone signal.

Claim 5

A signal selecting system for an electric musical instrument as claimed in claim 2, wherein said plurality of gating means each comprise memory means and signal-switching means, respectively, said memory means being connected to the respective parts of the transistor preference circuit for being set according to signals provided from the collectors of the respective transistors in said transistor preference circuit and memorizing the set state even after said signals from a collector have been removed, and said signal-switching means being connected to the memory means and being by the output signals from said memory means for switching the tone signals applied thereto on and off.

Claim 6

A signal-selecting system for an electric musical instrument as claimed in claim 3, wherein said signal-selecting system further comprises a detecting means having an input terminal connected to all of the output terminals of said plurality of memory means, said detecting means being for detecting a state when two or more memory means are set simultaneously and resetting said two or more memory means so that only one memory means corresponding to a keyswitch still closed after the reset operation is set.